Projection offset processor and the like



H. N. FAIRBANKS ETAL PROJECTION OFFSET PROCESSOR AND THE LIKE Dec. 20, 1966 Filed NOV. 12, 1964 VIII!" United States Patent 3,292,923 PROJECTION OFFSET PROCESSOR AND THE LIKE Henry N. Fairbanks and Daniel H. Robbins, Rochester,

N.Y., assignors to Itek Corporation, Lexington, Mass,

a corporation of Delaware Filed Nov. 12, 1964, Ser. No. 410,801 Claims. (Cl. 271-3) This invention relates to improved guide means for apparatus adapted to feed sheets of material through processing solutions, and more particularly to improved guide means for processors that are adapted to transport offset master sheets through processing solutions and that are often used in cooperation with associated equipment such as a projection printer.

Prior art sensitized sheet material processors have been found to be unsatisfactory for processing projection offset plate or master sheet material such as the material marketed by the assignee under the trademark Project- A-Lith.

This material is characterized by a paper sheet that is plastic coated on both surfaces and has a sensitized emulsion on topv of one of the plastic coatings. The overall thickness of this sheet is in the order of .007", and it is inherently stiff in contrast to typical sensitized paper. This stiffness increases the difficulty of transporting the sheets into, through, and out of processors. The problems of transportation are further increased by the emulsion surface becoming extremely soft as it is exposed to the developing agents. The soft emulsion ordinarily has a tendency to mar or become embossed during transportation, and any physical damage to the emulsion affects the quality of the final printed copy. Also, these offset master sheets have a tendency to curl, and as the emulsion is softened by its exposure to the developing agents,'such tendency to curl is increased. Such curl must be carefully controlled and compensated for so that the sheets are fed accurately through the proper paths without jamming or binding.

An object of the invention is improved feeding of offset master sheets into and out of processing equipment.

Another object of the invention is to compensate for the stiffness and tendency to curl of offset master sheets in feeding such sheets into and out of processing equipment.

Another object of the invention is to feed offset master sheets smoothly from a printer or other apparatus into a processor and to guide the processed sheets smoothly from a processor to a location convenient for the processor operator.

Another object of the invention is to feed an offset master sheet from one unit of equipment to another without sticking, binding, jamming, or marring the emulsion surface in spite of differences in the speeds of the sheet feed drive of the two units of equipment.

Another object of the invention is to invert an offset master sheet as it leaves a processor and to deposit such inverted offset master sheet within sight of the operator of the processor and an associated printer so that the operator can quickly and conveniently determine whether such offset master is a suitable one.

To these and other ends the invention resides in certain improvements and combinations, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of this specification.

In the drawings:

FIG. 1 shows a partial cross sectional view of guide means for feeding an offset master sheet into and out of a processor according to the invention; and

FIG. 2 shows an isometric view'of an offset master 3,292,923 Patented Dec. 20, 1966 processing unit positioned adjacent a printing unit for receiving offset master sheets from the printing unit, processing such sheets, and delivering them in the view and reach of the operator.

In one preferred arrangement as illustrated in FIG. 2, an offset master sheet processor 10 according to the invention is associated with other equipment such as printer 11. Chair 12 indicates the position of an operator of these associated units of equipment. An offset master sheet 13 is printed'in printer 11, fed to processor 10 where it is transported through processing solutions, and then delivered into the view of and within the convenient reach of an operator in chair 12. The processed offset master sheet 13, as deposited on top of processor 10, is oriented so that it can be read by an operator in chair 12.

The details of the operation of a processor according to the invention are best shown in the cross section view of FIG. 1. In this somewhat schematic representation, an offset master sheet 13 is shown as entering and leaving processor 10. The path of travel of offset master sheet 13 is from rollers 14 near the exit of printer 11, through an input guide 15 to processor 10, through processing solutions in processor 10, and through an output guide 32 and onto the top of processor 10. Offset master sheet 13 is preferably oriented emulsion side outward as it passes through the transporting means 16 within processor 10, so that the emulsion is fully and uniformly contacted by processing solutions within processor 10. The tendency to curl of offset mastersheet 13 is such that when oriented emulsion side out in the transporting means of processor 10, offset master sheet 13 tends to curl back upon its backside and thus bends its leading and trailing edges in against the transporting means. This tendency to curl, along with the inherent stiffness, of offset master sheet 13 is accurately compensated for by the invention as illustrated in processor 10.

As the leading edge of offset master sheet 13 passes beyond rollers 14 in printer 11, it is guided through an input guide 15 into processor 10. Input guide 15 in cross section has generally the shape of a curved horn with the wide end closest to rollers 14 and the narrow end near transporting drive means 16 in processor 10. The curved guide slot of input guide means 15 extends for substantially the full width of offset master sheet 13. Input guide means 15 can be conveniently formed of a backing plate 17 to which are secured guide wires 18 spaced along backing plate 17 for substantially the full width of offset master sheet 13. Opposed to wires 18 are a complementary plurality of guide wires 19 that are secured to support means 33. A protective hood 20 provides a safe shield enclosing input guide means 15 and completing the connective closure between printer 11 and processor 10.

The curved horn shape of input guide means 15 is arranged so as to allow a loop to be formed in offset master sheet 13 near rollers 14 and near the open end of input guide means 15, while at the same time, to control closely the path of offset master sheet 13 near the narrow end of input guide means 15 so as to direct the leading edge of sheet 13 accurately into the nip of drive means 16 in processor 10. The formation of a loop 21 in offset master sheet 13 allows for differences in driving speed between the sheet feeding means of printer 11 as represented by driven rollers 14 and drive means 16 in processor 10. Loop 21 is arranged to be near drive rollers 14 and the open end of curved input guide 15 rather than near drive means 16 in processor 10 so that such loop will be confined to a portion of the offset master sheet remote from its leading edge and the driven feed means 16 of processor 10. Allowing of any loop formation other than near the wide end of input guide means 15 has been found to cause buckling, folding, binding, jamming, or other malfunction in the feeding of an offset master sheet from printer 11 to processor 10.

As the leading edge of offset master sheet 13 passes beyond the narrow end of input guide means 15, it tends to curl upward as shown by broken lines, but is guided downward by guide wires 23 secured to backing plate 22 so as to be fed into the driven nip of feeding means 16 in processor 10.

After the leading edge of offset master sheet 13 is fed into the nip in feeding means 16 in processor 10, loop 21 can be allowed to form gradually near the wider end of input guide 15 as a result of the greater driving speed of rollers 14 relative to sheet feeding means 16. The preferred shape of input guide means 15 is such as to allow formation of loop 21, but to confine it to the open end of input guide means 15 and to keep it spaced from drive means 16 so that loop 21 will not interfere with smooth and accurate feeding of offset master sheet 13.

Offset master sheet 13 is then fed through a plurality of processing solutions in processor until the desired processing is completed, whereupon master 13 is fed out of processor 10. The leading edge of offset master sheet 13 is deflected away from drive means 16 by curved guide wires 24 that are secured to backing plate 25 so that the leading edge of offset master sheet 13 is directed into squeegee rollers 26 which remove excess processing solution.

As preferably oriented in its passage through sheet feeding means 16, offset master sheet 13 is emulsion side outward, and as it passes through squeegee rollers 26, it is oriented emulsion side downward. Hence to be readable by an operator, master sheet 13 must be inverted. This is accomplished according to the invention by guide wires 27 fastened to backing plate 28 to form an output chute or guide 32. Guide wires 27 cooperate with the natural curl of offset master sheet 13 to guide such sheet upward and over squeegee rollers 26 onto the top 29 of processor 10 where it is positioned emulsion side up and readable by an operator. Such inversion of offset master sheet 13 not only makes the offset master readable as deposited on top of processor 10, but also saves space and gives another function to the top 29 of processor 10.

Offset master sheets 13 of various lengths may be fed through processor 10 and through the outlet guide 32 onto the top 29 of processor 10, and the-shorterlengths of sheets tend to slide off of the top 29, back down under squeegee rollers 26, and into processor 10. To prevent any such obviously detrimental movement, stop wires 30 secured to backing plate 31 are arranged immediately beyond and below the nip of squeegee rollers 26 so as to catch the trailing edge of an offset master sheet 13 as it emerges from squeegee rolls 26 and to prevent any reverse motion of the sheet. Stop wires 30 are bent upward near squeegee rolls 26 so as to retain the trailing edge of offset master sheet 13 against any downward or reverse motion of the sheet. Thus, for masters 13 that are too short to reach a self supporting position of rest on the top 29 of processor 10, guide wires 30 prevent their sliding back into processor 10. For longer offset master sheets 13 which can maintain a position of rest on the top 29 of processor 10, the stop wires 30 lightly support trailing edges only.

The various guide wires such as 18, 19, 23, 24, 27, and 30 provide a plurality of raised ribs or ridges spaced along substantially the full width of offset master sheet 13 for controlled guiding. The various shaped guides according to the invention are provided with such raised ribs or ridges to reduce the friction and drag of wet master sheets moving relative to a guide. Alternative to guide wires, a guide plate may be corrugated or swaged to provide a plurality of raised ridges according to the invention. Such ently stiff and curled offset master sheets through the 4 various paths as required according to the invention without great expense in shaping guide means, and such means also offer a maximum of guiding with a minimum of contact with offset master sheets 13.

It will thus be seen that the inventive structure accomplishes the above stated objects, and while the invention has been disclosed herein *by reference to the details of a preferred embodiment, it is to be understood that such disclosure is intended in an illustrative rather than a limiting sense, and it is contemplated that various modifications of the construction and arrangement of the parts will readily occur to those skilled in the art Within the spirit of the invention and the scope of the appended claims.

We claim:

1. In a processor adapted to receive offset master sheets from associated equipment having independent sheet feeding means and to transport said offset master sheets through processing solutions, said processor having drive means for advancing said sheets, the improvement comprising: input means for receiving said sheets from said associated equipment, said input means including curved guide means formed with upper and lower walls having a curved horn-shape in cross section for receiving the leading edge of one of said sheets in the wide end of said guide means and guiding said leading edge through the narrow end of said guide means into a nip for said advancing'means, means for increasing the tangential drive velocity of said independent sheet feeding means relative to the tangential drive velocity of said sheet advancing means to form a loop in each of said sheets between said independent sheet feeding means of said associated equipment and said advancing means of said processor; and guide means consisting of substantially stationary components for guiding said sheets along an output path having'a direction which is gradually changing and extending from said advancing means through an outward path, an upward path, and a reverse path for inverting said sheets and depositing said sheets on top of said processor.

2. The processor of claim 1 wherein said curved hornshaped input guide means is arranged so that said loop formed is each of said sheets in confined to a portion of each of said sheets near said wide end of said guide means so as to be spaced from said nip.

3. The processor of claim 2 wherein said guide means comprises a plate provided with a plurality of raised ridges arranged for engaging said offset master sheet at spaced intervals transversely of said offset master sheet.

4. The processor of claim 1 wherein said output means comprises a sheet metal guide plate and means providing a plurality of raised ridges arranged at spaced intervals transversely of said offset master sheet.

5. In a processor for transporting offset master sheets through processing solutions and having drive means for advancing said sheets, the improvement comprising: roller squeegee means positioned beyond said advancing means for removing excess fluid from said sheets; and guide means consisting of substantially stationary components arranged beyond said roller squeegee means for guiding said sheets along an output path having a direction which is gradually changing and extending from said squeegee means and tending upward and over saidsqueegee means for inverting said sheets relative to their orientation of said squeegee means, and for depositing said sheets on a sheet receiving platform located above said squeegee means.

6. The apparatus of claim 5 wherein a stop means is arranged immediately beyond and below said squeegee means to prevent the trailing edges of said sheets from falling downward under said roller squeegee and into said processor.

7. In a processor adapted to receive offset master sheets from associated equipment having independent sheet feeding means and to transport said offset master sheets through processing solutions by means of drive means for advancing said sheets, means for guiding said offset master sheets, comprising: input means formed with upper and lower walls having a curved horn-shape in cross section and arranged for receiving the leading edges of said sheets in the wider end of said input means and for guiding said leading edges through the narrower end of said input means; first roller means positioned beyond the narrower end of said input means and having a hip for receiving said master sheet emerging from said input means, second roller means positioned beyond the Wider end of said input means for introducing said sheets into said input means and for driving said sheets at a higher velocity than the tangential velocity of said first roller means so as to allow formation of a loop in said sheets near said wide end of said input means.

8. The process of claim 7 wherein said guide means comprise a plurality of bearing ridges raised from backing plates and arranged at spaced intervals transversely of said offset master sheet.

9. The processor of claim 7 including output means arranged beyond said drive means for guiding said sheets through a path leading outward, upward, and back for inverting said sheets and depositing said sheets on top of said processor.

10. The processor of claim 9 wherein said output means comprises a sheet metal guide plate provided with a plurality of raised bearing ridges arranged at spaced intervals transversely of said offset master sheet.

References Cited by the Examiner UNITED STATES PATENTS 2,153,154 4/1939 Nivison et al 27l8 2,156,049 4/1939 Boerger.

2,292,781 8/ 1942 Erhardt et a1. 2718 2,341,368 2/1944 Flood.

2,721,078 10/ 1955 Caps 27l9 2,878,742 3/1959 Trump 271-- X 2,901,246 8/1959 Wagner 27 13 2,977,868 4/1961 Dutch 9494 2,981,171 4/1961 Hruby et al. 95-94 3,033,351 5/1962 Dutch.

3,227,444 1/ 1966 Egan 271--65 RAPHAEL M. LUPO, Primary Examiner. 

5. IN A PROCESSOR FOR TRANSPORTING OFFSET MASTER SHEETS THROUGH PROCESSING SOLUTIONS AND HAVING DRIVE MEANS FOR ADVANCING SAID SHEETS, THE IMPROVEMENT COMPRISING: ROLLER SQUEEGEE MEANS POSITIONED BEYOND SAID ADVANCING MEANS FOR REMOVING EXCESS FLUID FROM SAID SHEETS; AND GUIDE MEANS CONSISTING OF SUBSTANTIALLY STATIONARY COMPONENTS ARRANGED BEYOND SAID ROLLER SQUEEGEE MEANS FOR GUIDING SAID SHEETS ALONG AN OUTPUT PATH HAVING A DIRECTION WHICH IS GRADUALLY CHANGING AND EXTENDING FROM SAID SQUEEGEE MEANS AND TENDING UPWARD AND OVER SAID SQUEEGEE MEANS FOR INVERTING SAID SHEETS RELATIVE TO THEIR ORIENTATION OF SAID SQUEEGEE MEANS, AND FOR DEPOSITING SAID SHEETS ON A SHEET RECEIVING PLATFORM LOCATED ABOVE SAID SQUEEGEE MEANS. 